Distributed server's failure response program product, server load balancing device, and server load balancing method

Abstract

In a device according to the present invention, a failed server session persistence information managing unit transfers relevant session persistence information from a session persistence information storing unit to a failed server session persistence information storing unit, upon receipt of a failure detection notice from a distributed server. A session persistence information retrieving unit searches the session persistence information storing unit upon inquiry about session persistence information, and further searches the failed server session persistence information storing unit when information corresponding to the inquiry cannot be extracted from the session persistence information storing unit. A service error response processing unit sends a predetermined service error response to a client when the corresponding information is extracted from the failed server session persistence information storing unit.

1 . A distributed server's failure response program product for processing a computer program which causes a computer to function as, during server load balancing processing for distributing client's requests to distributed servers operable as a distribution destination, session persistence maintaining processing means to allocate a series of requests within a session uniquely to a particular distributed server and responding to a failure in a distributed server associated with a session being subjected to the session persistence maintaining processing, the distributed server's failure response program product comprising the step of: 
 causing the computer to function as failed server session persistence information management means for, upon receipt of a distributed server's failure detection notice, extracting and deleting, from session persistence information storage means that stores session persistence information in which a session to be subjected to the session persistence maintaining processing and a distributed server allocated with the session are recorded, session persistence information of a session handled by the notified failed distributed server, then generating failed server session persistence information in accordance with the extracted session persistence information, and storing the generated failed server session persistence information in failed server session persistence information storage means;    causing the computer to function as failed server session persistence information retrieval means for, upon receipt of an inquiry request as to whether a session is subjected to the session persistence maintaining processing, retrieving session persistence information of the inquired session from the session persistence information storage means, and further retrieving failed server session persistence information of the inquired session from the failed server session persistence information storage means when the session persistence information of the inquired session is not stored in the session persistence information storage means; and    causing the computer to function as service error response processing means for executing predetermined service error response processing for a requestor client of the inquired session when the failed server session persistence information of the inquired session is extracted as a result of the retrieval of the failed server session persistence information retrieval means.    
   
   
       2 . The distributed server's failure response program product according to  claim 1 , further comprising the step of: 
 causing the computer to function as service error response processing definition information storage means for storing, for each service executed in a session between the distributed server and a client, service error response processing definition information that defines details of the service error response processing for a failure that occurs in the distributed server during the session persistence maintaining processing for the session, wherein    when the session persistence information contains at least information for identifying a service executed in a session, the failed server session persistence information management means generates the failed server session persistence information containing the information for identifying a service in accordance with the session persistence information, and    when the failed server session persistence information of the inquired session is extracted, the service error response processing means executes the service error response processing in accordance with the service error response processing definition information corresponding to a service identified by the failed server session persistence information.    
   
   
       3 . The distributed server's failure response program product according to  claim 2 , wherein the service error response processing definition information contains a definition regarding a format and response method of a response message to the client.  
   
   
       4 . A server load balancing device executing, during server load balancing processing for distributing requests from a client to distributed servers operable as a distribution destination, session persistence maintaining processing to allocate a series of requests within a session uniquely to a particular distributed server, the server load balancing device comprising: 
 a session persistence information storage unit for storing session persistence information in which a session to be subjected to the session persistence maintaining processing and a distributed server allocated with the session are set;    a failed server session persistence information management unit for, upon receipt of a distributed server's failure detection notice, extracting and deleting session persistence information of a session handled by the notified failed distributed server from the session persistence information storage unit, then generating failed server session persistence information in accordance with the extracted session persistence information, and storing the generated failed server session persistence information in a failed server session persistence information storage unit;    a failed server session persistence information retrieval unit for, upon receipt of an inquiry request as to whether a session is subjected to the session persistence maintaining processing, retrieving session persistence information of the inquired session from the session persistence information storage unit, and further retrieving failed server session persistence information of the inquired session from the failed server session persistence information storage unit when the session persistence information of the inquired session is not stored in the session persistence information storage unit; and    a service error response processing unit for executing predetermined service error response processing for a requester client of the inquired session when the failed server session persistence information of the inquired session is extracted as a result of the retrieval of the failed server session persistence information retrieval unit.    
   
   
       5 . The server load balancing device according to  claim 4 , further comprising: 
 a service error response processing definition information storage unit for storing, for each service executed in a session between the distributed server and a client, service error response processing definition information that defines details of the service error response processing for a failure that occurs in the distributed server during the session persistence maintaining processing for the session, wherein    when the session persistence information contains at least information for identifying a service executed in a session, the failed server session persistence information management unit generates the failed server session persistence information containing the information for identifying a service in accordance with the session persistence information, and    when the failed server session persistence information of the inquired session is extracted, the service error response processing unit executes the service error response processing in accordance with the service error response processing definition information corresponding to a service identified by the failed server session persistence information.    
   
   
       6 . The server load balancing device according to  claim 4 , wherein the service error response processing definition information contains a definition regarding a format and response method of a response message to the client.  
   
   
       7 . A server load balancing method for executing, during server load balancing processing for distributing requests from a client to distributed servers operable as a distribution destination, session persistence maintaining processing to allocate a series of requests within a session uniquely to a particular distributed server, the method comprising the steps of: 
 upon receipt of a distributed server's failure detection notice, extracting and deleting, from session persistence information storage means that stores session persistence information in which a session to be subjected to the session persistence maintaining processing and a distributed server allocated with the session are recorded, session persistence information of a session handled by the notified failed distributed server, then generating failed server session persistence information in accordance with the extracted session persistence information, and storing the generated failed server session persistence information in failed server session persistence information storage means;    upon receipt of an inquiry request as to whether a session is subjected to the session persistence maintaining processing, retrieving session persistence information of the inquired session from the session persistence information storage means, and further retrieving failed server session persistence information of the inquired session from the failed server session persistence information storage means when the session persistence information of the inquired session is not stored in the session persistence information storage means; and    executing predetermined service error response processing for a requestor client of the inquired session when the failed server session persistence information of the inquired session is extracted as a result of the step of retrieving the failed server session persistence information.    
   
   
       8 . The server load balancing method according to  claim 7 , further comprising the step of: 
 storing, for each service executed in a session between the distributed server and a client, service error response processing definition information that defines details of the service error response processing for a failure that occurs in the distributed server during the session persistence maintaining processing for the session, wherein,    when the session persistence information contains at least information for identifying a service executed in a session, in the step of generating failed server session persistence information, generated is the failed server session persistence information containing the information for identifying a service in accordance with the session persistence information is generated, and    when the failed server session persistence information of the inquired session is extracted, in the step of executing predetermined service error response processing, executed is the service error response processing in accordance with the service error response processing definition information corresponding to a service identified by the failed server session persistence information.    
   
   
       9 . The server load balancing method according to  claim 7 , wherein the service error response processing definition information contains a definition regarding a format and response method of a response message to the client.